Crane research in ND has far-reaching impact

JAMESTOWN, N.D. – Flying vast migration circuits, the midcontinent population of sandhill cranes travels from wintering grounds in the American Southwest and northern Mexico to breeding grounds from Quebec to northeastern Russia.

The cranes spend time in Nebraska, South Dakota and North Dakota, where they are hunted.

Research on the birds also is wide-reaching, but some of the most critical work is being done in the U.S. Geological Survey’s Northern Prairie Wildlife Research Center at Jamestown.

“For whatever reason, (the Russia-breeding cranes) picked a couple of the harshest environments,” said Gary Krapu, a wildlife biologist at Northern Prairie – the inhospitable deserts of Mexico and the cold wetlands of Siberia.

Information gathered by Krapu and his research team has led to more detailed information about the cranes, but it’s also helped determine hunting season and bag limits for the cranes in North Dakota.

And it’s taken decades of work funded by the USGS, the states of the Central Flyway, the U.S. Fish and Wildlife Service and the International Crane Foundation to get this far.

“The studies that we’re finishing up now started in 1997,” said Krapu, who originally started researching the sandhill cranes in 1977.

For him, the work began as a telephone call from Washington, D.C., when a chief of research asked if he’d like to be in charge of a project Congress had approved the day before.

Prior to that, Krapu had been working on other waterfowl projects.

His work with sandhill cranes, however, would certainly have a longer reach – both in time and geographically.

Like most cranes, the sandhill crane is a gawky creature and has a bright red forehead and rusty-speckled gray feathers. Their wingspan is about 5 feet in length, and they are smaller than their endangered cousins, the whooping cranes.

They aren’t especially friendly, either, and when caught the birds do peck, scratch and kick – brutally hard – anywhere they can reach, agreed Krapu and Aaron Pearse, another wildlife biologist at Northern Prairie.

The midcontinent population of the cranes is the largest in the world at 600,000 birds, and unlike most of the other crane populations, that population can be legally hunted.

During their fall migration, the sandhill cranes live mostly on grain, and their meat isn’t much different from that of geese, Krapu said.

Properly defining sandhill subpopulations has been part of hunting management for the species, and part of that has been determining the geographic distribution of the birds, especially during the fall and winter seasons.

For Krapu and the many field workers who have contributed essential work to the study, that has meant tagging cranes with satellite transmitters.

Dave Brandt, a wildlife biologist at Northern Prairie, was responsible for handling most of the field operations of the project – trapping, tagging and tracking the birds, as well as managing massive amounts of data from the project.

That management, Krapu said, made it possible to conduct complex studies over vast areas.

For the sandhill crane project, workers trapped the birds along the Platte and the North Platte rivers in Nebraska, where nearly the whole population stops together in the spring, Pearse said.

Field researchers then placed the small, tube-shaped devices around plastic leg bands on one leg each of more than 175 cranes.

The devices are lightweight, and while the older models were battery-powered and shut themselves off after approximately one and a half years, more recent transmitters are solar-powered and keep working for three to five years – all the while sending location information to Northern Prairie.

The devices also are durable enough that cranes can fly, walk or immerse themselves without damaging the transmitters.

“They seem to live their lives about the same,” Pearse said. “They breed and do the same things all the other ones do.”

Most of the cranes were tagged between 1998 and 2004, though some from different groups of birds from Russia have been tagged more recently.

Because almost all of that population of cranes visits Nebraska each spring, a plan could be devised to obtain a random sample that would represent the entire population. And through tracking those cranes, researchers could find out exactly where, and how far, those distance-flying sandhill cranes were going when they departed from Nebraska.

“Cranes are fairly unique for the scale of the area” of their migration, Krapu said, and they have been making the trip from Mexico to Siberia for a very long time. “They could well have been making it for half a million years or more.”

As data from the trackers came in, the wildlife scientists began to learn where different parts of that sandhill population go in the fall and winter, linking where the cranes breed to where they stay in the winter.

All that is vital information for wildlife managers, who use it to set hunting limits while still allowing the sandhill cranes to thrive as a species, Krapu said.

The second, more recent part of the crane study has focused on the spring migration, monitoring the birds’ locations but also their eating habits and how much fat they put on before the breeding season.

The third portion of the study has focused on the Russia link. Between June and September, about 23 percent of that population of sandhill cranes nests in northeastern Russia, with its productive wetlands and the many rivers flowing into the Arctic Ocean.

The cranes can be found from the northeastern tip of Siberia west to the Lena River, and as far south as the Kamchatka Peninsula. In the past 60 years or so, the sandhill cranes have been expanding their range west, too – all nesting in remote areas. The numbers of cranes nesting in Russia have doubled since the 1970s, Krapu said.

“I’m working with a Russian biologist on that, from the Russian Academy of Science,” he said.

Much of the information the team of scientists has gathered from Russia comes from monitoring the tagged sandhill cranes. And more work is being conducted on the breeding grounds in Siberia.